The nature of the liver alpha-adrenergic receptor and the effects of its activation on cell calcium movements, glycogen metabolism and gluconeogenesis will be studied. This will involve: 1) characterization of the binding of (3H)catecholamines to alpha and beta adrenergic receptors in liver plasma membranes, 2) correlation of such binding to the effects of catecholamines on cell calcium fluxes, phosphorylase activation and pyruvate kinase inactivation, 3) analysis of the nature and mechanisms of the cell calcium changes induced by alpha-adrenergic activation, 4) analysis of the role of cytosolic calcium in the effects of alpha-adrenergic activation on phosphorylase, glycogen synthase and pyruvate kinase, 5) analysis of the role of calcium in the regulation of hepatic adenylate cyclase by catecholamines.